A known synchromesh device for a transmission is disclosed in JP2000-329159A (which will be referred to as reference 1 hereinafter). According to the synchromesh device in reference 1, chamfers are respectively formed at a sleeve, a synchronizer ring and a gear piece. According to reference 1, a shape of the chamfer of the synchronizer ring is modified in order to reduce a gear noise at the time of shifting.
According to the synchromesh device for the transmission, a function where the chamfer of the sleeve contacts the chamfer of the synchronizer ring to achieve a synchronization before a thrust-through operation and a function where the chamfer of the sleeve thrusts through the gear piece to complete shifting may not be actualized at the same time. In other words, when the shape of the chamfer of the sleeve is designed so as to establish an appropriate balk ratio of the synchronizer ring and so as to achieve the synchronization, a shift load required for moving the sleeve so as to thrust through the gear piece is increased and therefore, a shift feeling may be worsened. In contrast, when the shape of the chamfer of the sleeve is designed so as to reduce the shift load required for moving the sleeve so as to thrust through the gear piece, the appropriate balk ratio of the synchronizer ring and the synchronization are not easily achieved, as a result, the gear noise may occur.
A need thus exits for a synchromesh device for a transmission, which is not susceptible to the drawback mentioned above.